What is the recommended treatment for herpes simplex infection in pregnant women?

Treatment of Herpes Simplex Infection in Pregnant Women

Acyclovir is the first-choice treatment for herpes simplex virus (HSV) infections during pregnancy, with valacyclovir as an acceptable alternative. 1 Both medications are effective for treating active HSV infections and can be used as suppressive therapy to prevent recurrences and reduce the risk of transmission to the neonate.

Treatment Recommendations by Clinical Scenario

First Episode of Genital Herpes During Pregnancy

• First clinical episode: Treat with oral acyclovir 200 mg 5 times daily or valacyclovir 1000 mg twice daily for 5-10 days 2
• In cases of severe or life-threatening HSV infection (e.g., disseminated infection, encephalitis, pneumonitis, or hepatitis), intravenous acyclovir is indicated 1

Recurrent Episodes During Pregnancy

• Episodic treatment: Acyclovir 200 mg 5 times daily or valacyclovir 500 mg twice daily 2
• Suppressive therapy: For women with frequent or severe recurrences, daily suppressive therapy should be considered 1

Suppressive Therapy in Late Pregnancy

• Begin at 36 weeks gestation for women with either:
  • History of first episode during current pregnancy
  • History of recurrent genital herpes 1, 2
• Recommended regimens:
  • Valacyclovir 500 mg twice daily 1, 3
  • Acyclovir 400 mg three times daily 4

Benefits of Suppressive Therapy

Suppressive antiviral therapy starting at 36 weeks gestation significantly:

• Reduces clinical HSV recurrences at delivery (by 60-75%) 3, 5, 6
• Decreases cesarean deliveries for active HSV lesions 3, 6
• Reduces HSV viral shedding at delivery 6

Delivery Management

• Active first episode at delivery: Cesarean delivery is recommended 2
• First episode within 6 weeks of delivery: Cesarean delivery is recommended 2
• Active recurrence at delivery: Cesarean delivery is recommended when membranes are intact; vaginal delivery may be considered with prolonged rupture of membranes 2
• No active lesions: Vaginal delivery is permitted 1

Safety in Pregnancy

• Acyclovir has the most extensive safety data in pregnancy and is the preferred agent 1, 7
• No pattern of adverse pregnancy outcomes has been reported with acyclovir exposure 1
• The Acyclovir Pregnancy Registry has not shown increased risk of major birth defects compared to the general population 7
• Valacyclovir (which converts to acyclovir in the body) also appears safe based on available data 7

Important Considerations and Pitfalls

Risk Assessment

• The risk of neonatal HSV transmission varies significantly:
  • 30-50% with primary first episode near delivery
  • 25-44% with non-primary first episode at delivery
  • Only about 1% with recurrent episode at delivery 1, 2

Common Pitfalls to Avoid

1. Failure to distinguish between first episode and recurrent infection - Treatment approach and risk of transmission differ significantly
2. Delaying treatment - Prompt initiation of antiviral therapy is essential for first episodes
3. Not offering suppressive therapy - Women with history of HSV should be offered suppression starting at 36 weeks
4. Unnecessary cesarean deliveries - In the absence of active lesions or prodromal symptoms, vaginal delivery is appropriate

Special Situations

• Acyclovir-resistant HSV: Rare in immunocompetent patients; if suspected, consult infectious disease specialists. IV foscarnet is the treatment of choice 1
• HIV co-infection: Increases risk of perinatal HIV transmission; aggressive HSV suppression is warranted 1

By following these evidence-based recommendations, clinicians can effectively manage HSV infections during pregnancy, minimize maternal symptoms, and significantly reduce the risk of neonatal herpes infection.